There is a growing need for adequate knife sharpeners that can be used in a commercial application as well as in the home. Frequent sharpening of knives in commercial locations such as restaurants, food processing plants and the like is often required. Knife sharpening services provide sharp knives on a regular basis for these locations but the knives also require frequent dressing of the blade to keep it as sharp as needed. Most individuals at these locations use the hand held sharpening hone that has been used for ages and takes a good deal of dexterity to achieve a good edge along with having the possibility of cutting the operator when the knife is drawn toward the hand holding the honing device. When using this type of hone the angle of the knife is determined by the way the individual is holding the knife and hone, and may very with each stroke of the knife.
Various design's of knife sharpeners have been proposed in the past for purpose of sharpening knives providing some of the improvements needed, such as using the sharpening rods disposed in a crossed relationship giving a precise angle to the edge being sharpened, but requiring the sharpening rods to be turned manually to relocate the sharpening surface. The act of automatically rotating the sharpening rods may seem to be minimal, but during the sharpening action, the knife is often drawn through the device several times. In a commercial application, this operation will occur a great number of times each day. Most of these devices additionally have not addressed the capability of easily changing the sharpening rods to achieve different sharpening surface textures.
Numerous innovations for knife sharpeners have been provided in the prior art that are described as follows. Even though these innovations may be suitable for the specific individual purposes to which they address, they differ from the present design as hereinafter contrasted. The following is a summary of those prior art patents most relevant to this application at hand, as well as a description outlining the difference between the features of the automatic rotation knife sharpener and the prior art.
U.S. Pat. No. 4,530,188 of Louis N. Graves describes a pocketsize sharpening apparatus of the variety carrying sharpening rods disposed in crossed relationship. The sharpening apparatus has a body with a distal face carrying clips to releasably secure a pair of sharpening rods in crossed relationship. A major access opening permits access to portions of the sharpening rods from a proximal face of the body for sharpening a blade. The major access opening has a V-shaped portion extended inward from a mouth with convergent edges disposed in parallel relationship to and exposing convergent portions of the sharpening rods from the proximal face. A minor access opening is comprised as a slot extending inward of the body toward the major opening a sufficient distance to expose opposite intersecting portions of the sharpening rods. A peripheral protective lip can line the major and minor openings on the proximal face of the body. A groove can be provided in the body wherein the sharpening rods can be seated and manually held in side-by-side, parallel relationship for the sharpening of pointed objects.
This patent describes a pocket-sized sharpener with stationary crossing sharpening rods. With this device, the sharpening of a knife will always be on the same surface unless the sharpening rods are removed and replaced in a different position. The device requires that it be held in one hand with the knife held in the other risking injury to the hand holding the device if the knife were to be placed incorrectly.
U.S. Pat. No. 4,624,079 of Mario J. Bonapace tells of a knife sharpener having a pair of abrasive rod members whose bottom ends are mounted on carriages that are reciprocally mounted in channels formed in upstanding block members. The channels travel along an axis that is parallel to the downwardly sloping top surface of the block members. The block members are fixedly attached to the top surface of a base and the mouths of their channels face each other and are aligned on parallel offset axes. The rod members therefore intersect each other at a predetermined angle to form a V at their top into which a knife blade is drawn rearward along a horizontal plane to sharpen its edges. Each of the carriages has one of its ends fixedly attached to a spring whose opposite end is fixedly held in position. The downward force of the knife blade as it is being sharpened causes the rod members on the respective carriages to travel downward toward each other and when the pressure is released, the springs will return them to their initial unloaded positions.
This patent describes a knife sharpener having a pair of abrasive rod members whose bottom ends are mounted on carriages. This is another knife sharpener with crossing sharpening rods having the same problem where the sharpening action takes place on the same location of the sharpening rods, unless they are physically removed and repositioned.
U.S. Pat. No. 4,646,477 of William M. Robertson discloses a knife sharpener that includes a pair of arms pivoted together at their inner ends about a shaft to provide continuous adjustment of the angular orientation between sharpening sticks which are seated in the outer ends of the handles for continuous rotational adjustment, in order to provide precise sharpening.
This patent describes another knife sharpener with crossing sharpener rods. The sharpening rods may be rotated within their holders manually, but the holders are on a pivot allowing for different angle preferences. The sharpening rod holders do not have an adequate securing device to hold them in position. The device must also be held in one hand directly below the sharpening action of the knife blade.
U.S. Pat. No. 6,881,137 of Daniel D. Friel, Sr. describes a sharpener for blades that comprises a physical structure supporting at least one abrasive surface. A displaceable guiding plate having an integral linear structural feature of the support is disposed toward one side of the abrasive surface. The linear structural feature provides sliding contact with a face of the blade to establish the relative angle of the plane of the edge facet of the blade with the plane of the abrasive surface at the point of mutual contact as the facet is guided into contact with the abrasive surface.
This patent describes a structure supporting at least one angled abrasive surface. The knife rest against a guide surface during the sharpening operation but will always make contact with the same surface unless that surface is manually rotated.
U.S. Pat. No. 4,912,885 of Mario J. Bonapace describes a knife sharpener having a base, a pair of leg assemblies, a cover, and a pair of rod members formed of abrasive material. The leg assemblies each have an elongated leg member having a pivot pin passing downwardly there through to secure the leg member to the top surface of the base. The pivot ends of the respective leg assemblies are secured to the base at a position adjacent each other so that their free motion ends can pivot toward and away from each other. A spring is connected to the leg assemblies for maintaining a pressure that will force the free motion ends of the respective leg members apart from each other. The rod members are detachably supported in apertures formed in the top surface of the free motion ends of the respective leg members and the respective apertures are angularly oriented toward each other so that the rod members cross paths with one another to form a V and it is within this V that the blade of a knife would be passed in order to sharpen the cutting edge of the knife. The downward force of the knife blade when it is being sharpened causes the rod members on the respective leg members to pivot toward each other and when the pressure is released the spring will return them to their initial unloaded positions.
This patent of Mario J. Bonapace describes a similar knife sharpener described in this application with many of the same features accept that the sharpening rods do not rotate. The sharpening rods make contact with the knife at the same surface each time the device is used, unless they are manually repositioned. The sharpening rods are not held in place by magnets and are not easily removed. There is no place to store them on the device.
U.S. Pat. No. 7,172,500 of Wen-Chiu Wu discloses a knife sharpener that has a housing, a base, a sharpening device and an adjustable device. The housing has a case, a cavity and a slot. The cavity is defined in the case and the slot is defined in the case and communicates with the cavity. The base is mounted on the housing and has a base board and two side walls formed on the base board. The sharpening device is movable mounted on the base and is received inside the housing. The sharpening device has two sharpening arms with sharpening rods. The adjustable device is mounted on the sharpening device mounted between the two sharpening arms. When the knife sharpener is used, the adjustable device is rotated to change the cross-position of the sharpening device. Therefore, a knife may be sharpened at a different site on the sharpening rods for prolonging the life span of the knife sharpener.
This patent discloses a knife sharpener that when the device is used, the adjustable mechanism is rotated to change the cross-position on the sharpening rods. Therefore, a knife may be sharpened at a different site on the sharpening rods for a prolonged life span of the knife sharpener. With this device, the sharpening rods are moved up and down but are not rotated automatically along with the fact that the sharpening rods are not easily replaced.
None of these previous efforts, however, provides the benefits attendant with the automatic rotation knife sharpener. The present design achieves its intended purposes, objects and advantages over the prior art devices through a new, useful and unobvious combination of method steps and component elements, with the use of a minimum number of functioning parts, at a reasonable cost to manufacture, and by employing readily available materials.
In this respect, before explaining at least one embodiment of the in detail it is to be understood that the design is not limited in its application to the details of construction and to the arrangement, of the components set forth in the following description or illustrated in the drawings. The automatic rotation knife sharpener is capable of other embodiments and of being practiced and carried out in various ways. In addition, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for designing of other structures, methods and systems for carrying out the several purposes of the present design. It is important, therefore, that the claims be regarded as including such equivalent construction insofar as they do not depart from the spirit and scope of the present application.